When your shipment's checkpoints increased, you'll get the event payload as below:
{
"event_type": "shipment.tracking.checkpoints.created",
"resource_type": "shipment",
"resource_id": "ESTEST00000",
"tracking_status": {
"easyship_shipment_id": "ESTEST00000",
"platform_order_number": "#100001",
"origin": "US",
"destination": "CA",
"company_order_number": "#100001",
"status": "Delivered",
"tracking_number": "12345",
"tracking_page_url": "https://www.trackmyshipment.co/shipment-tracking/ESTEST00000",
"checkpoints": {}
}
}